Particulate materials are often processed either in batch or continuous operations. For example, rotating drums can be used to dry particulate material and/or coat particular material with a sprayed solution. The materials being processed are of various types. For example, pharmaceutical tablets are coated in rotating drums, in both batch and continuous operations. Agricultural seeds are also coated with pesticides, herbicides, and fungicides in rotating drums. Cereals and snack foods are also processed in rotating drums to add flavor, which is sprayed onto the particles and then dried. These processes may require sampling of the product for quality assurance. Various prior art sampling techniques exist. For example, an operator can reach into the machine with a scoop to retrieve product. However, such a manual sampling process may be prohibited by process parameters, such as temperature and airflow conditions which require that the door of the machine stay sealed. Also, manual sampling of the product may create contamination concerns, which must be avoided. Manual sampling also creates safety issues, particularly due to dangers of the machine mechanics or biological hazards of certain products or coating solutions.
Various automatic sampling systems have been developed to overcome the problems with manual sampling. Vacuum transport is known for moving or transferring products, but has one major drawback when used for product sampling. Generally, a basic vacuum transfer system is good at moving all of the product from a specified area to another location, however, does not provide a discrete sample volume. Limiting the vacuum to a specific time period limits the volume of product that is suctioned, but still allows for various sample volumes, due to the difficultly in controlling the amount of product that is vacuumed up by the system. Such a vacuum system is not satisfactory where precision and repeatability are critical for validation, such as in the pharmaceutical industry.
Therefore, a primary objective of the present invention is the provision of an improved discrete volume vacuum sampling system for particulate materials.
Another objective of the present invention is the provision of an improved device for sampling a discrete volume of particulate material from a bed of material.
A further objective of the present invention is the provision of an improved method of obtaining a discrete volume sample of particulate material from a bed of material.
Another objective of the present invention is the provision of a product sampling device using a vacuum to obtain a discrete volume of product for sampling.
Still another objective of the present invention is the provision of a vacuum system for product sampling wherein a container door is automatically closed when the vacuum is applied and automatically opened when the vacuum is released.
Another objective of the present invention is the provision of a product vacuum sampling system which discharges excess product back into the product bed.
Another objective of the present invention is the provision of is a discrete volume vacuum sampling system which is simple and accurate.
These and other objectives will become apparent from the following description of the invention.